The work proposed is directed toward meeting the objectives of the Arizona SCOR, i.e., to elucidate the pathogeneses, pathophysiology, natural histories and factors contributing to the development of airway obstructive diseases (AOD) in order to prevent, detect, and/or treat AOD. To accomplish this, seven closely related projects, supported by Core units, comprise a multidisciplinary program involving and combing epidemiological, clinical, pathophysiological, experimental, and radiological approaches to the AOD problem. The prospective longitudinal epidemiological survey of the 4000 members of 1650 Tucson households will continue to study the role of environmental, host, and genetic factors, including atopy, asthma, and history of bronchiolitis or other childhood respiratory illness, in contributing to the risk of developing chronic bronchitis, emphysema, or other chronic obstructive pulmonary disease (COPD), and provides further opportunity to evaluate methods for early detection of subclinical COPD. Air versus helium oxygen flow-volume curves and chest radiographs will be evaluated in this context. In subpopulations, there are specific studies of the role of aeroallergens, atopy and IgE levels, airway reactivity, or alpha-1-antitrypsin Pi MZ phenotype in development of AOD. Pediatric lung function tests are being developed and will be utilized to study childhood airways diseases and their long-term consequences. Experimental studies are being employed to relate structure to function in canine models of AOD and in excised lung preparations and human autopsy material, combining physiological measurements with simultaneous roentgenographic image magnification and subsequent morphometry and refinements of high resolution radiologic imaging will continue.